Process for the preparation of styryl-cyclopropanecarboxylic acid esters and intermediate products for this process

ABSTRACT

A process for the preparation of a styryl-cyclopropane-carboxylic acid ester of the formula ##STR1## in which R is C 1-4  -alkyl or an alcohol radical customary in pyrethroids, 
     R 1  is alkoxy or alkylthio, either of which may be optionally substituted by halogen, 
     R 2  is hydrogen or alkoxy, or 
     R 1  and R 2  together are optionally halogen-substituted alkylenedioxy, and 
     R 3  is hydrogen or chlorine, comprising reacting a compound of the formula ##STR2## with, respectively, one, two or three equivalents of a base at a temperature below 60° C. The products are insecticidally active when R is the residue of a pyrethroid-type alcohol. Various syntheses are given for the starting materials which are new.

The present invention relates to an unobvious process for thepreparation of certain styryl-cyclopropane-carboxylic acid esters, andto new intermediate products for carrying out this process and theirpreparation.

It has already been disclosed that certain esters of3-styryl-2,2-dimethylcyclopropanecarboxylic acids have insecticidalproperties (German Offenlegungsschrift (German Published Specification)2,738,150). They are prepared by linking the C-C double bond of thestyryl group by a Wittig reaction, in which butyl-lithium is used as thebase and which must be carried out at -78° C. under an inert gas. Thissynthesis route is not practical for an industrial preparation.

Furthermore, the 2,2-dimethyl-3-formyl-1-carboxylic acid ester used asthe starting material for this reaction is available industrially onlywith difficulty.

1. The present invention now provides a process for the preparation of astyryl-cyclopropane-carboxylic acid ester of the general formula##STR3## in which R represents C₁₋₄ -alkyl or an alcohol radicalcustomary in pyrethroids,

R¹ represents alkoxy or alkylthio, either of which may be optionallysubstituted by halogen,

R² represents hydrogen or alkoxy, or

R¹ and R² together represent optionally halogen-substitutedalkylenedioxy and

R³ represents hydrogen or chlorine, in which (a) a compound of thegeneral formula ##STR4## or (b) a compound of the general formula##STR5## or (c) a compound of the general formula ##STR6## in whichformulae R¹, R², R³ and R have the meanings indicated above, is reactedwith, respectively, one, two or three equivalents of a base, ifappropriate in the presence of a diluent, between -20° C. and +60° C.

2. It has furthermore been found that the compounds of the formula (I)are preferably obtained when the reaction is carried out below 50° C.

3. The compounds of the general formula (II) in which

R, R¹, R² and R³ have the meanings indicated above, are new.

4. The compounds of the general formula (III) in which

R¹, R² and R have the meanings indicated under 1. (above), are new.

5. The compounds of the general formula (IV) in which

R¹ and R² have the meanings indicated above, are new.

6. A process has also been found for the preparation of a compound ofthe general formula (II), which is characterised in that (a) hydrogenchloride is split off from a compound of the formula (III) by the actionof heat, or (b) a compound of the formula (IV) is reacted with analcohol of the general formula

    R--OH                                                      (XIII),

in which

R has the meaning indicated under 1, or (c) a compound of the generalformula ##STR7## in which R¹ and R² have the meanings indicated above,is reacted with at least two equivalents of phosphorus pentachloride,and the resulting reaction solution is then reacted with an alcohol ofthe general formula

    R--OH                                                      (XIII),

in which

R has the meaning indicated under 1, or (d) a compound of the generalformula ##STR8## in which R¹ and R² have the meanings indicated above,is reduced, water is split off from the compound obtained and theproduct is reacted with a chlorinating agent in the presence of analcohol of the formula (XIII), R therein having the meaning indicatedabove, or, successively, the lactone ring is first opened with achlorinating agent and the product is then reacted with the alcohol.

7. A process has also been found for the preparation of a compound ofthe general formula (III), which is characterized in that a compound ofthe general formula ##STR9## in which R¹, R² and R have the meaningsindicated under 1. (above), is reacted with phosphorus pentachloride ina diluent below 30° C.

8. A process has also been found for the preparation of a compound ofthe general formula (IV), characterized in that a compound of thegeneral formula ##STR10## in which R¹ and R² have the meanings indicatedabove, is reacted with at least two equivalents of phosphoruspentachloride in a diluent below 30° C.

9. The compounds of the formula (V) in which

R¹, R² and R have the meanings indicated under 1. (above), are new.

10. A process has also been found for the preparation of a compound ofthe general formula (V), characterized in that a compound of the formula(VI) is reacted with a chlorinating agent in the presence of an alcoholof the formula (XIII), R therein having the meaning indicated under 1,or, successively, the lactone ring is first opened with a chlorinatingagent and the product is then reacted with the alcohol.

11. The new compounds of the general formula (VI) in which

R¹ and R² have the meanings indicated above, have also been found.

12. A process has also been found for the preparation of a compound ofthe general formula (VI), characterized in that a compound of thegeneral formula ##STR11## in which R denotes C₁ -C₄ -alkyl, is reactedwith a compound of the general formula ##STR12## in which R¹ and R² havethe meanings indicated under 1 and

Hal denotes halogen, preferably chlorine, in the presence of aFriedel-Crafts catalyst.

13. It has also been found that a compound of the general formula##STR13## in which R¹ represents alkoxy or alkylthio and

R² represents hydrogen or alkoxy or, together with R¹, alkylenedioxy, isobtained by a process in which a compound of the general formula##STR14## in which R¹ and R² have the meanings indicated above, isreacted with the acid chloride of the formula ##STR15## in the presenceof a Friedel-Crafts catalyst and, if appropriate, in the presence of adiluent.

14. The compound of the formula (XI) is prepared by a process in whichthe compound of the formula ##STR16## is reacted with a chlorinatingagent.

The styrylcyclopropanecarboxylic acid esters of the formula (I), whichcontain a radical of an alcohol customary in pyrethroids and which canbe prepared by process 1 according to the invention, have anarthropodicidal, especially an insecticidal and acaricidal, action.Preferably, process 1 is employed for the preparation ofstyryl-cyclopropanecarboxylic acid derivatives of the formula (I)

in which

R¹ represents C₁ -C₄ -alkoxy, C₁ -C₄ -alkylthio, C₁ -C₂ -fluoroalkoxy,C₁ -C₂ -chlorofluoroalkoxy or C₁ -C₂ -fluoroalkylthio,

R² represents hydrogen or methoxy or, together with R¹, C₁ -C₂-alkylenedioxy or C₁ -C₂ -fluoroalkylenedioxy,

R³ represents chlorine and

R represents C₁ -C₄ -alkyl or the radical of an optionally substitutedphenoxybenzyl alcohol of the general formula ##STR17## wherein R⁴represents hydrogen, cyano or ethynyl and

R⁵ and R⁶ represent hydrogen or fluorine. If6-(4'-methoxy-phenyl)-4,6-dichloro-3,3-dimethylhex-5-enoic acid ethylester is used as the starting material in process variant 1(a), thecourse of the reaction can be illustrated by the following equation.##STR18##

The general formula (II) provides a definition of the starting materialswhich can be used in process variant 1(a). In this formula, R, R¹ and R²preferably represent the radicals indicated above as preferred and R³represents chlorine.

The compounds of the formula (II) have not hitherto been disclosed inthe literature; their preparation is described below.

If 6-(4'-methoxy-phenyl)-4,6,6-trichloro-3,3-dimethylhexanoic acidmethyl ester is used as the starting material in process variant 1(b),the course of the reaction can be illustrated by the following equation:##STR19##

The general formula (III) provides a definition of the startingmaterials which can be used in process variant 1(b). The preferredsubstituents R¹, R² and R are the same as those indicated above. Thecompounds of the formula (III) have not hitherto been disclosed in theliterature; their preparation is described below.

If 6-(4'-methoxy-phenyl)-4,6,6-trichloro-3,3-dimethylhexanoic acidchloride is used as the starting material in process 1(c), the course ofthe reaction can be illustrated by the following equation: ##STR20##

The general formula (IV) provides a definition of the starting materialswhich can be used in process variant 1(c). The preferred substituents R¹and R² are the same as those indicated above. The compounds of theformula (IV) have not hitherto been disclosed in the literature; theirpreparation is described below.

Process variants 1(a), (b) and (c) are carried out by reacting thestarting substances (II), (III) and (IV) with, respectively, 1, 2 or 3equivalents of a base, if appropriate in the presence of a diluent.

An alcoholate, such as sodium methylate, potassium ethylate, sodiumethylate, sodium isopropylate, sodium tert.-butyrate or potassiumtert.-butyrate is preferably used as the base.

The alcohol corresponding to the base is preferably employed as thediluent, but other inert diluents, for example hydrocarbons, such astoluene, xylene or cyclohexane, or chlorinated hydrocarbons, such aschlorobenzene, or ethers, such as diisopropyl ether, tetrahydrofuran ordioxane, can also be used, additionally or exclusively.

The process is carried out at a temperature between -20° C. and +60° C.,preferably between 20° C. and 50° C.

A similar reaction is described in DE-OS (German PublishedSpecification) 2,539,896. However, while the temperature range preferredin this publication is between 60° and 100° C. (page 31) when sodiummethylate or sodium ethylate is used, only very little product of theformula (I) is obtained under these conditions, but a further mol ofhydrogen halide is predominantly split off, a triple bond being formed.

Surprisingly, it has been found that this can be avoided if the reactionis carried out below 60° C.

Another advantage of the process according to the invention is that onlyone of the 4 possible stereoisomers is very preferentially formed. Ithas the trans-configuration, relative to the cyclopropane ring.

The insecticidal and acaricidal esters of this isomeric configurationdisplay a particularly good activity.

The following cyclopropanecarboxylic acid esters of the formula (I) arepreferably prepared by process 1:2,2-dimethyl-3-[2'-chloro-2'-(4"-trifluoromethylmercaptophenyl)-vinyl]-cyclopropane-1-carboxylicacid methyl ester and ethyl ester,2,2-dimethyl-3-[2'-chloro-2'-(3",4"-dimethoxy-phenyl)-vinyl]-cyclopropane-1-carboxylicacid methyl ester and ethyl ester,2,2-dimethyl-3-[2'-chloro-2'-(4"-bromo-phenyl)-vinyl]-cyclopropane-1-carboxylicacid methyl ester and ethyl ester,2,2-dimethyl-3-[2'chloro-2'-(3",4"-trifluoroethylenedioxy-phenyl)-vinyl]-cyclopropane-1-carboxylicacid methyl ester and ethyl ester,2,2-dimethyl-3-[2'-chloro-2'-(3"-trifluoromethylmercapto-phenyl)-vinyl]-cyclopropane-1-carboxylicacid methyl ester and ethyl ester,2,2-dimethyl-3-[2'-chloro-2'-(4"-methylmercapto-phenyl)-vinyl]-cyclopropane-1-carboxylicacid methyl ester and ethyl ester,2,2-dimethyl-3-[2'-chloro-2'-(4"-ethoxy-phenyl)-vinyl]-cyclopropane-1-carboxylicacid methyl ester and ethyl ester, 2,2-dimethyl-3-[2'-chloro-2'-(4"-methoxy-phenyl)-vinyl]-cyclopropane-1-carboxylic acid methyl ester andethyl ester,2,2-dimethyl-3-[2'-chloro-2'-(4"-trifluoromethoxyphenyl)-vinyl]-cyclopropane-1-carboxylicacid methyl ester and ethyl ester,2,2-dimethyl-3-[2'-chloro-2'-(3"-trifluoromethoxy-4"-chloro-phenyl)-vinyl]-cyclopropane-1-carboxylicacid methyl ester and ethyl ester and2,2-dimethyl-3-(2'-chloro-2'-(3",4"-methylenedioxy-phenyl)-vinyl]-cyclopropane-1-carboxylicacid methyl ester and ethyl ester.

The compounds of the general formula (II) are new. They are obtained bythe process indicated under 6, by (a) splitting off hydrogen chloridefrom compounds of the general formula (III) by the action of heat or (b)reacting compounds of the formula (IV) with alcohols, or (c) reactingcompounds of the formula (VI) with phosphorus pentachloride and thenreacting the product with an alcohol, or (d) reducing compounds of theformula (VI), splitting off water from the compounds obtained andreacting the products with an chlorinating agent in the presence of analcohol, or, successively, first opening the lactone ring with achlorinating agent and then reacting the product with an alcohol.

If 6-(4'-methoxy-phenyl)-4,6,6-trichloro-3,3-dimethylhexanoic acid ethylester is used as the starting material in process 6(a), the course ofthe reaction can be represented by the following equation: ##STR21##

The general formula (III) provides a definition of the startingsubstances which can be used in process 6(a). The preferred substituentsR¹, R² and R are the same as those for process variant 1(a).

The compounds of the formula (III) are new; their preparation isdescribed below.

Process 6(a) is carried out by warming the starting substances of theformula (III), if appropriate in a diluent, to a temperature between 25°and 80° C., preferably to a temperature between 30° and 50° C. Duringthis procedure, hydrogen chloride is split off. Preferred diluents arehydrocarbons, such as benzene, toluene, xylene, benzine, cyclohexane orpetroleum ether; chlorinated hydrocarbons, such as methylene chloride,chloroform, carbon tetrachloride, dichloroethane or chlorobenzene; andnitriles, such as acetonitrile.

If appropriate, isolation of the compounds of the general formula (III)can be dispensed with, so that process 6(a) immediately follows process7 (see below).

If 6-(4'-methoxy-phenyl)-4,6,6-trichloro-3,3-dimethylhexanoic acidchloride is used as the starting substance in process 6(b), the courseof the reaction can be represented by the following equation: ##STR22##

The general formula (IV) provides a definition of the startingsubstances which can be used in process 6(b). The preferred substituentsR¹ and R² are the same as those in the case of process variant 1(a).

The compounds of the formula (IV) are new; their preparation isdescribed below.

Process 6(b) is carried out by adding an alcohol of the general formulaR--OH, the preferred meaning of R being the same as that in the case ofprocess variant 1(a), to the starting substance of the formula (IV), ifappropriate in a diluent, at a temperature between -20° C. and +80° C.,preferably between 0° C. and 30° C. In order to bring the reaction tocompletion, the mixture is then stirred for a further period at elevatedtemperature, preferably between 30° and 60° C. Excess alcohol can beused as the diluent, as can any of the solvents which can also be usedin process 6(a).

If 3,3-dimethyl-4-(4'-methoxy-phenacyl)-γ-butyrolactone and ethanol areused as starting substances in process 6(c), the course of the reactioncan be represented by the following equation: ##STR23##

The general formula (VI) provides a definition of the startingsubstances which can be used in process 6(c). The preferred substituentsR¹ and R² are the same as those in the case of process variant 1(a). Thecompounds of the formula (VI) are new; their preparation is describedbelow.

Phosphorus pentachloride can be used as the chlorinating agent.

Process 6(c) is carried out by a procedure in which the startingsubstance of the general formula (VI) is initially introduced and isreacted with at least two equivalents of the chlorinating agent. Aslight excess is favorable.

In contrast to the generally customary procedure (Houben-Weyl, volume V,3, page 912 et seq.) for the reaction of ketones with phosphoruspentachloride, the process is preferably carried out in the presence ofa diluent. Preferred diluents are the same as those mentioned forprocess 6(a).

Using a diluent and metering in the phosphorus pentachloride, it ispossible, surprisingly, to avoid the otherwise customary side reactions,for example chlorination in the α-position relative to the carbonylgroup or addition of hydrogen chloride onto the chlorovinyl group.

The reaction temperature is between -20° C. and +60° C., preferablybetween 0° C. and 35° C.

Subsequent esterification is effected by adding excess alcohol R-OHdropwise, analogously to process 6(b).

The mixture is worked up by washing the organic phase until neutral andseparating it off, and distilling off the solvent and the phosphoricacid ester. Purification by distillation at this stage can usually bedispensed with.

If 3,3-dimethyl-4-(methoxy-phenacyl)-γ-butyrolactone is used as thestarting material in process 6(d), the course of the reaction can berepresented by the following equation: ##STR24##

The general formula (VI) provides a definition of the startingsubstances which can be used in process 6(d). The preferred andparticularly preferred substituents R¹ and R² are the same as those inthe case of process variant 1(a). The compounds of the formula (VI) arenew; their preparation is described below.

In principle, any of the agents by which a ketone is reduced to thealcohol without the lactone ring being attacked can be used as thereducing agent. Examples which may be mentioned are: a complexborohydride, such as sodium borohydride, or hydrogen in the presence of,for example, a nickel catalyst, palladium catalyst or platinum catalyst,such as Raney nickel. Sodium borohydride is preferred.

Process 6(d) is carried out by a procedure in which, after the reducingstep, which is carried out in a manner which is in itself customary, theproduct is dehydrated, that is to say water is split off.

An acid catalyst is preferably employed for the dehydration. Exampleswhich may be mentioned are: oxalic acid, sulphuric acid, phosphoricacid, potassium bisulphate, p-toluenesulphonic acid, aluminum oxide andsilicates. In addition, it is possible to split off acetic acid byheating after acetylation of the alcohol. The acetylation is carried outwith acetyl chloride or acetic anhydride. The third step of process 6(d)corresponds to process 10 (see below).

If 6-(3'-methoxy-phenyl)-6-oxo-4-chloro-3,3-dimethylhexanoic acid ethylester is used as the stating substance in process 7, the course of thereaction can be represented by the following equation: ##STR25##

The general formula (V) provides a definition of the starting substanceswhich can be used in process 7. The preferred substituents R¹, R² and Rare the same as those in the case of process variant 1(a). The compoundsof the formula (V) are new; their preparation is described below.

It has been found that the compounds (III) are obtained from thecompounds of the formula (V) only when the reaction is carried out in adiluent below 30° C.

Process 7 is carried out by a procedure in which the starting substanceof the general formula (V) is dissolved in a diluent. Preferred diluentsare the same as those mentioned for process 6(a), especially petroleumether, cyclohexane, toluene and chlorobenzene.

The reaction temperature is between -20° C. and +30° C., preferablybetween 0° and 25° C.

The mixture is worked up by adding ice-water, washing the organic phaseuntil neutral and distilling off the solvent.

The structure is proved by a nuclear magnetic resonance spectrum.

If 3,3-dimethyl-4-(4'-methoxy-phenacyl)-γ-butyrolactone is used as thestarting substance in process 8, the course of the reduction can berepresented by the following equation: ##STR26##

The general formula (VI) provides a definition of the startingsubstances which can be used in process 8. The preferred substituentsare the same as in the case of process 1(a). The compounds of theformula (VI) are new; their preparation is described below.

It has furthermore been found that the compounds (IV) are obtained fromthe compounds (VI) only if the reaction is carried out in a diluentbelow 30° C.

Process 8 is carried out by a procedure in which the starting substanceof the general formula (VI) is dissolved in a diluent.

Preferred diluents are the same as those mentioned for process 6(a),especially petroleum ether, cyclohexane, toluene and chlorobenzene.

The reaction temperature is between -20° and +30° C., preferably between0° and 25° C.

The compounds of the formula (IV) can be isolated by distilling off thesolvent and phosphorus oxychloride under gentle conditions, or they canbe directly reacted further according to process variant 1(c) or process6(b).

If 3,3-dimethyl-4-(4'-methoxy-phenacyl)-γ-butyrolactone and ethanol areused as starting substances in process 10, the course of the reactioncan be represented by the following equation: ##STR27##

The general formula (VI) provides a definition of the startingsubstances which can be used in process 10. The preferred substituentsR¹ and R² are the same as those in the case of process variant 1(a). Thecompounds of the formula (VI) are new; their preparation is describedbelow.

The second starting substance for process 10 is an alcohol of theformula R-OH, the preferred meaning of R being the same as that in thecase of process variant 1(a).

The following chlorinating agents can be used in process 10: hydrogenchloride, thionyl chloride, phosgene or phosphorus trichloride, andhydrogen chloride and thionyl chloride are preferred; if appropriate,dimethylformamide is used as a catalyst.

Lactone ring openings of this type are known in principle, but in nocase do such lactones contain an additional carbonyl group. Conditionstherefore had to be found to achieve a process in which only the desiredreaction proceeds and not, for example, (1) acid-catalyzedself-condensations of the ketone (acetophenone, for example, reacts withitself in this manner under catalysis by hydrogen chloride) and (2)chlorination of the carbonyl group or of the hydrogen atoms in theα-position relative to the carbonyl group.

Process 10 is carried out by a procedure in which the starting substanceof the formula (VI) is dissolved in an alcohol of the formula R-OH, ifappropriate a diluent is also added and the chlorinating agent is thenpassed in or added dropwise. An exothermic reaction starts; in order toavoid the above-mentioned side reactions, the temperature should in nocase exceed 80° C., but the reaction is preferably carried out between20° and 50° C.

Preferred diluents are, in particular, benzene, toluene, benzine,petroleum ether, cyclohexane, chlorobenzene or xylene.

In principle, it is also possible first to open the lactone ring andthen to add the alcohol. In this case, the starting compound (VI), ifappropriate in one of the diluents mentioned, is heated to temperaturesbetween 50° and 80° C. (higher temperatures are not appropriate), achlorinating agent being added, if appropriate under pressure. Thealcohol R-OH is then added dropwise or pumped in.

The resultant compound of the formula (V) is isolated by distilling offthe solvent under gentle conditions. Further purification is difficult,but also unnecessary. The crude compounds of the formula (V) can be useddirectly for process 7.

If 3,3-dimethyl-pent-4-enoic acid methyl ester and p-methoxy-benzoylchloride are used as starting substances in process 12, the course ofthe reaction can be represented by the following equation: ##STR28##

The general formulae (VII) and (VIII) provide definitions of thestarting substances which can be used in process 12. The preferredsubstituents R¹, R² and R³ are the same as those in the case of process1(a). The compounds of the formula (VII) (DT-OS (German PublishedSpecification) 2,539,895) and (VIII) are known.

Examples of compounds of the formula (VIII) are: 4-methoxybenzoylchloride, 4-trifluoromethoxy-benzoyl chloride,3-trifluoromethylmercapto-benzoyl chloride,3-trifluoromethoxy-4-chlorobenzoyl chloride, 3,4-methylenedioxy-benzoylchloride, 3,4-dimethoxybenzoyl chloride,4-trifluoromethylmercapto-benzoyl chloride, 4-ethoxybenzoyl chloride and3,4-trifluoroethylenedioxy-benzoyl chloride.

Possible catalysts are Friedel-Crafts catalysts. The particularlypreferred catalyst is tin tetrachloride, or, if appropriate, mixturescontaining aluminum chloride, titanium tetrachloride, zinc chloride oriron(III) chloride. If aluminum chloride is used by itself, thecompounds formed are not those of the formula (VI) but those of theformula (V). The Friedel-Crafts catalyst is employed in an equimolaramount or in an amount which is less than or more than the equimolaramount. Process 12 can be carried out with or without a diluent. If adiluent is used, possible diluents are methylene chloride, chloroform,dichloroethane, tetrachloroethane, nitromethane or nitrobenzene.

The process according to the invention is carried out by a procedure inwhich the Friedel-Crafts catalyst, if appropriate in a diluent, isinitially introduced and the acid halide of the general formula (VIII)is added, while cooling. An ester of the general formula (VII) is thenadded dropwise at temperatures between -25° C. and +50° C., preferablyat temperatures between 0° C. and 25° C.

However, it is also possible to initially introduce an acid halide ofthe formula (VIII), together with an ester of the formula (VII), ifappropriate in the presence of a diluent, and then to meter in theFriedel-Crafts catalyst.

To accelerate the reaction, when mixing of the reactants has ended, thereaction can be carried out at elevated temperature, for example at 25°to 150° C., preferably at 30° to 100° C. The end of the reaction can berecognized by the end of the evolution of gas. After rendering themixture acid, it is worked up in the customary manner by extraction. Thecrude product of the general formula (VI) can be purified byrecrystallization.

The course of the reaction is extremely surprising, since lactoneformation under conditions which are so mild was hitherto unknown.

If anisole and 3,3-dimethyl-4-chlorocarbonylmethyl-γ-butyrolactone areused as starting substances in process 13 for the preparation of thecompounds of the formula (VI), the course of the reaction can berepresented by the following equation: ##STR29##

The formula (X) and (XI) provide definitions of the starting substanceswhich can be used in process 13. The compound (XI) is new; itspreparation is described below.

The compounds of the formula (X) are known, and examples which may bementioned are: ethoxybenzene, methylmercaptobenzene, anisole,benzodioxole and pyrocatechol dimethyl ether. Possible catalysts are inprinciple any of the customary Friedel-Crafts catalysts, such asaluminum chloride, tin tetrachloride, titanium tetrachloride, hydrogenfluoride, boron trifluoride, iron(III) chloride, zinc chloride,polyphosphoric acids, perfluoroalkanesulphonic acids (optionally inpolymeric form) and optionally mixtures thereof.

The process is preferably carried out in the presence of a diluent.Possible diluents are: methylene chloride, chloroform, dichloroethane,tetrachloroethane, nitrobenzene and nitromethane. Methylene chloride ispreferred.

The reaction is extremely surprising, since it had to be expected thatthe lactone ring would also react, in the following manner: ##STR30##and in addition cyclization to give the tetralone was to be expected.Ring openings of 5-membered lactone rings using aromatics by aFriedel-Crafts reaction in the manner formulated above are known andtake place under very mild conditions (Houben-Weyl; volume VI, 2, page812 et seq.).

That such a reaction of the lactone with the aromatics of the formula(X) does not take place is also surprising, especially since theFriedel-Crafts catalyst must be employed in at least an equimolaramount, and even better in excess.

Process 13 is preferably carried out as follows:

The acid chloride (XI) is initially introduced in a diluent, and theFriedel-Crafts catalyst is added at a temperature between -10° and +5°C. The aromatic compound is then added dropwise, if appropriate likewisedissolved in a diluent. If very active Friedel-Crafts catalysts (forexample aluminum chloride or tin tetrachloride) are used, this procedureis carried out at -10° to +5° C., and in the case of less activeFriedel-Crafts catalysts (for example zinc chloride, iron chloride,titanium tetrachloride or perfluoroalkanesulphonic acids), the aromaticcompounds are added dropwise at room temperature. The mixture is thensubsequently stirred at room temperature; in the case of less activecatalysts the reaction must be carried out at elevated temperature ifnecessary.

If aromatics which are slow to react, for example chlorobenzene, areused, it is advisable not to accelerate the reaction by increasing thetemperature but to extend the reaction times in order to preventundesired lactone ring opening in the above-mentioned sense.

The mixture is worked up in the customary manner; the lactones can bepurified by recrystallization.

Process 14 can be represented by the following equation: ##STR31##

The acid of the formula (XII) used as the starting substance is known(J. Org. Chem., volume 38, page 4148 and J. Chem. Soc. 79, 763), but theacid chloride of the formula (XI) is not. It appears surprising that theacid is converted smoothly into the acid chloride, since under theseconditions ring opening of the lactone usually also takes place.

Process 14 is carried out under the conditions which are customary forpreparing an acid chloride from an acid. Preferred chlorinating agentsare thionyl chloride and phosgene. However, care must be taken thatreaction times which are as short as possible are applied, in order toavoid a side reaction in the above-mentioned sense. The mixture isworked up in the customary manner. The acid chloride can be purified bydistillation or can be employed in the crude form in process 13.

The styrylcyclopropanecarboxylic acid esters of the formula (I) whichcontain a radical of an alcohol customary in pyrethroids are welltolerated by plants, have a favorable level of toxicity to warm-bloodedanimals, and can be used for combating arthropod pests, especiallyinsects and acarids, which are encountered in agriculture, in forestry,in the protection of stored products and of materials, and in thehygiene field. They are active against normally sensitive and resistantspecies and against all or some stages of development. Theabovementioned pests include:

from the class of the Isopoda, for example Oniscus asellus,Armadillidium vulgare and Porcellio scaber;

from the class of the Diplopoda, for example Blaniulus guttulatus;

from the class of the Chilopoda, for example Geophilus carpophagus andScutigera spec.;

from the class of the Symphyla, for example Scutigerella immaculata;

from the order of the Thysanura, for example Lepisma saccharina;

from the order of the Collembola, for example Onychiurus armatus;

from the order of the Orthoptera, for example Blatta orientalis,Periplaneta americana, Leucophaea maderae, Blattella germanica, Achetadomesticus, Gryllotalpa spp., Locusta migratoria migratorioides,Melanoplus differentialis and Schistocerca gregaria;

from the order of the Dermaptera, for example Forficula auricularia;

from the order of the Isoptera, for example Reticulitermes spp.;

from the order of the Anoplura, for example Phylloxera vastatrix,Pemphigus spp., Pediculus humanus corporis, Haematopinus spp. andLinognathus spp.;

from the order of the Mallophaga, for example Trichodectes spp. andDamalinea spp.;

from the order of the Thysanoptera, for example Hercinothrips femoralisand Thrips tabaci;

from the order of the Heteroptera, for example Eurygaster spp.,Dysdercus intermedius, Piesma quadrata, Cimex lectularius, Rhodniusprolixus and Triatoma spp.;

from the order of the Homoptera, for example Aleurodes brassicae,Bemisia tabaci, Trialeurodes vaporariorum, Aphis gossypii, Brevicorynebrassicae, Cryptomyzus ribis, Doralis fabae, Doralis pomi, Eriosomalanigerum, Hyalopterus arundinis, Macrosiphum avenae, Myzus spp.,Phorodon humuli, Rhopalosiphum padi, Empoasca spp., Euscelis bilobatus,Nephotettix cincticeps, Lecanium corni, Saissetia oleae, Laodelphaxstriatellus, Nilaparvata lugens, Aonidiella aurantii, Aspidiotushederae, Pseudococcus spp. and Psylla spp.;

from the order of the Lepidoptera, for example Pectinophora gossypiella,Bupalus piniarius, Cheimatobia brumata, Lithocolletis blancardella,Hyponomeuta padella, Plutella maculipennis, Malacosoma neustria,Euproctis chrysorrhoea, Lymantria spp., Bucculatrix thurberiella,Phyllocnistis citrella, Agrotis spp., Euxoa spp., Feltia spp., Eariasinsulana, Heliothis spp., Laphygma exigua, Mamestra brassicae, Panolisflammea, Prodenia litura, Spodoptera spp., Trichoplusia ni, Carpocapsapomonella, Pieris spp., Chilo spp., Pyrausta nubilalis, Ephestiakuehniella, Galleria mellonella, Cacoecia podana, Capua reticulana,Choristoneura fumiferana, Clysia ambiguella, Homona magnanima andTortrix viridana;

from the order of the Coleoptera, for example Anobium punctatum,Rhizopertha dominica, Bruchidius obtectus, Acanthoscelides obtectus,Hylotrupes bajulus, Agelastica alni, Leptinotarsa decemlineata, Phaedoncochleariae, Diabrotica spp., Psylliodes chrysocephala, Epilachnavarivestis, Atomaria spp., Oryzaephilus surinamensis, Anthonomus spp.,Sitophilus spp., Otiorrhynchus sulcatus, Cosmopolites sordidus,Ceuthorrhynchus assimilis, Hypera postica, Dermestes spp., Trogodermaspp., Anthrenus spp., Attagenus spp., Lyctus spp., Meligethes aeneus,Ptinus spp., Niptus hololeucus, Gibbium psylloides, Tribolium spp.,Tenebrio molitor, Agriotes spp., Conoderus spp., Melolontha melolontha,Amphimallon solstitialis and Costelytra zealandica;

from the order of the Hymenoptera, for example Diprion spp., Hoplocampaspp., Lasius spp., Monomorium pharaonis and Vespa spp.;

from the order of the Diptera, for example Aedes spp., Anopheles spp.,Culex spp., Drosophila melanogaster, Musca spp., Fannia spp., Calliphoraerythrocephala, Lucilia spp., Chrysomyia spp., Cuterebra spp.,Gastrophilus spp., Hyppobosca spp., Stomoxys spp., Oestrus spp.,Hypoderma spp., Tabanus spp., Tannia spp., Bibio hortulanus, Oscinellafrit, Phorbia spp., Pegomyia hyoscyami, Ceratitis capitata, Dacus oleaeand Tipula paludosa;

from the order of the Siphonaptera, for example Xenopsylla cheopis andCeratophyllus spp.;

from the class of the Arachnida, for example Scorpio maurus andLatrodectus mactans;

from the order of the Acarina, for example Acarus siro, Argas spp.,Ornithodoros spp., Dermanyssus gallinae, Eriophyes ribis, Phyllocoptrutaoleivora, Boophilus spp., Rhipicephalus spp., Amblyomma spp., Hyalommaspp., Ixodes spp., Psoroptes spp., Chorioptes spp., Sarcoptes spp.,Tarsonemus spp., Bryobia praetiosa, Panonychus spp. and Tetranychusspp..

The active compounds can be converted into the customary formulations,such as solutions, emulsions, suspensions, powders, dusting agents,foams, pastes, soluble powders, granules, aerosols, suspension-emulsionconcentrates, seed-treatment powders, natural and synthetic materialsimpregnated with active compound, very fine capsules in polymericsubstances, coating compositions for use on seed, and formulations usedwith burning equipment, such as fumigating cartridges, fumigating cansand fumigating coils, as well as ULV cold mist and warm mistformulations.

These formulations may be produced in known manner, for example bymixing the active compounds with extenders, that is to say liquid orliquefied gaseous or solid diluents or carriers, optionally with the useof surface-active agents, that is to say emulsifying agents and/ordispersing agents and/or foam-forming agents. In the case of the use ofwater as an extender, organic solvents can, for example, also be used asauxiliary solvents.

As liquid diluents or carriers, especially solvents, there are suitablein the main, aromatic hydrocarbons, such as xylene, toluene or alkylnaphthalenes, chlorinated aromatic or chlorinated aliphatichydrocarbons, such as chlorobenzenes, chloroethylenes or methylenechloride, aliphatic or alicyclic hydrocarbons, such as cyclohexane orparaffins, for example mineral oil fractions, alcohols, such as butanolor glycol as well as their ethers and esters, ketones, such as acetone,methyl ethyl ketone, methyl isobutyl ketone or cyclohexanone, orstrongly polar solvents, such as dimethylformamide anddimethylsulphoxide, as well as water.

By liquefied gaseous diluents or carriers are meant liquids which wouldbe gaseous at normal temperature and under normal pressure, for exampleaerosol propellants, such as halogenated hydrocarbons as well as butane,propane, nitrogen and carbon dioxide.

As solid carriers there may be used ground natural minerals, such askaolins, clays, talc, chalk, quartz, attapulgite, montmorillonite ordiatomaceous earth, and ground synthetic minerals, such ashighly-dispersed silicic acid, alumina and silicates. As solid carriersfor granules there may be used crushed and fractionated natural rockssuch as calcite, marble, pumice, sepiolite and dolomite, as well assynthetic granules of inorganic and organic meals, and granules oforganic material such as sawdust, coconut shells, corn cobs and tobaccostalks.

As emulsifying and/or foam-forming agents there may be used non-ionicand anionic emulsifiers, such as polyoxyethylene-fatty acid esters,polyoxyethylene-fatty alcohol ethers, for example alkylaryl polyglycolethers, alkylsulphonates, alkyl sulphates, aryl sulphonates as well asalbumin hydrolysis products. Dispersing agents include, for example,lignin sulphite waste liquors and methylcellulose.

Adhesives such as carboxymethylcellulose and natural and syntheticpolymers in the form of powders, granules or latices, such as gumarabic, polyvinyl alcohol and polyvinyl acetate, can be used in theformulations.

It is possible to use colorants such as inorganic pigments, for exampleiron oxide, titanium oxide and Prussian Blue, and organic dyestuffs,such as alizarin dyestuffs, azo dyestuffs or metal phthalocyaninedyestuffs, and trace nutrients, such as salts of iron, manganese, boron,copper, cobalt, molybdenum and zinc.

The formulations in general contain from 0.1 to 95 percent by weight ofactive compound, preferably from 0.5 to 90 percent by weight.

The active compounds according to the invention may be used in the formof their formulations of the types that are commercially available or inthe use forms prepared from these formulations.

The active compound content of the use forms prepared from theformulations of the types that are commercially available can varywithin wide ranges. The active compound concentration of the use formscan be from 0.0000001 to 100% by weight of active compound, preferablyfrom 0.0001 to 10% by weight.

The compounds may be employed in a customary manner appropriate for theparticular use forms.

When used against pests harmful to health and pests of stored products,the active compounds are distinguished by an excellent residual activityon wood and clay as well as a good stability to alkali on limedsubstrates.

The present invention also provides an arthropodicidal compositioncontaining as active ingredient a compound of the present invention inadmixture with a solid or liquefied gaseous diluent or carrier or inadmixture with a liquid diluent or carrier containing a surface-activeagent.

The present invention also provides a method of combating arthropods(especially insects or acarids) which comprises applying to thearthropods, or to a habitat thereof, a compound of the present inventionalone or in the form of a composition containing as active ingredient acompound of the present invention in admixture with a diluent orcarrier.

The present invention further provides crops protected from damage byarthropods by being grown in areas in which immediately prior to and/orduring the time of the growing a compound of the present invention wasapplied alone or in admixture with a diluent or carrier.

It will be seen that the usual methods of providing a harvested crop maybe improved by the present invention.

The invention is further described in the following illustrativeexamples:

EXAMPLE 1 (process variant 1(a))

A solution of sodium ethylate (prepared from 2.5 g of sodium and 100 mlof ethanol) was added dropwise to a solution of 34.5 g (0.1 mol) of6-(4'-methoxy-phenyl)-4,6-dichloro-3,3-dimethyl-hex-5-enoic acid ethylester in 100 ml of ethanol at room temperature. The mixture wassubsequently stirred for 4 hours, diluted with ice-water and renderedneutral. After extraction with methylene chloride, the organic phase wasdried and concentrated on a rotary evaporator. Distillation under a highvacuum gave 26.5 g of a pale yellowish oil of boiling point 162°-168°C./0.08 mbar. It contained all the 4 possible stereoisomers of2,2-dimethyl-3-[2'-chloro-2'-(4"-methoxy-phenyl)]-vinyl-cyclopropane-1-carboxylicacid ethyl ester. The vinyl proton of the main isomers showed (in CDCl₃)a doublet at δ=5.7 and 5.85 ppm. Mass spectrum: m/e=308.

EXAMPLE 2 (process variant 1(b))

A solution of 38.2 g of6-(4'-methoxy-phenyl)-4,6,6-trichloro-3,3-dimethyl-hexanoic acid ethylester (crude; from Example 8) in 100 ml of ethanol was added dropwise toa solution of 4.75 g of sodium in 250 ml of ethanol at room temperature.The mixture was subsequently stirred at room temperature for 2 hours andthen heated to 50° C. for a further 1 hour. Ice-water was then added andthe mixture was neutralized with 10% strength hydrochloric acid. Afterextraction twice with methylene chloride, the organic phases were driedand concentrated on a rotary evaporator and the residue was distilledunder a high vacuum. 25 g of2,2-dimethyl-3-[2'-chloro-2'-(4"-methoxy-phenyl)]-vinyl-cyclopropane-1-carboxylicacid ethyl ester of boiling point 155°-163° C./0.05 mbar were obtained.

EXAMPLE 3 (process variant 1(c))

A solution of 40 g of sodium in 700 ml of ethanol was added to asolution of 35 g of6-(4'-methoxy-phenyl)-4,6,6-trichloro-3,3-dimethyl-hexanoic acidchloride (crude, still containing POCl₃ ; from Example 9) in 500 ml oftoluene, while cooling with ice. The mixture was stirred at roomtemperature for 8 hours and then heated to 50° C. for a further 1 hour,ice-water was added, the mixture was neutralized with 10% strengthhydrochloric acid, the toluene phase was separated off and the aqueousphase was washed with methylene chloride. The combined organic phaseswere dried and the solvents and the phosphoric acid triethyl esterformed were distilled off. The residue was purified by distillationunder a high vacuum. 18.6 g of2,2-dimethyl-3-[2'-chloro-2'-(4"-methoxy-phenyl)]-vinylcyclopropane-1-carboxylicacid ethyl ester were obtained.

EXAMPLE 4 (process variant 1(c))

2,2-Dimethyl-3-[2'-chloro-2'-(4"-methylmercaptophenyl)]-vinylcyclopropane-1-carboxylicacid ethyl ester was obtained from6-(4"-methylmercaptophenyl)-4,6,6-trichloro-3,3-dimethyl-hexanoic acidchloride and sodium ethylate analogously to Example 3.

EXAMPLE 5 (process 6(a))

A solution of6-(4'-methoxy-phenyl)-4,6,6-trichloro-3,3-dimethyl-hexanoic acid methylester in toluene was warmed to about 40° C. for 1 hour. After distillingoff the toluene in vacuo,6-(4'-methoxy-phenyl)-4,6-dichloro-3,3-dimethyl-hex-5-enoic acid methylester remained. The structure was proved by the NMR spectrum.

EXAMPLE 6 (process 6(b))

20 times the equimolar amount of dry methanol was added to a solution of6-(4'-methoxy-phenyl)-4,6,6-trichloro-3,3-dimethyl-hexanecarboxylic acidchloride (crude still contained POCl₃ ; from Example 9) in toluene at20° C. and the mixture was then warmed to 40° C. for a further 1 hour.After subsequently stirring the mixture for 4 hours (without heating)the solvents and the phosphoric acid ester were removed in vacuo. Theresidue was identical to the product obtained in Example 5.

EXAMPLE 7 (process variant (6(c))

46 g of phosphorus pentachloride were added to a solution of 26.2 g of3,3-dimethyl-4-(4'-methoxy-phenacyl)-γ-butyrolactone in 400 ml oftoluene and the mixture was stirred at room temperature until all thePCl₅ had dissolved. 120 ml of ethanol were then added dropwise at 20° C.and thereafter the mixture was warmed to 45° C. for 1 hour andsubsequently stirred further until it reached room temperature again. Itwas then poured into a large amount of ice-water and rendered neutral.The toluene phase was separated off, dried and concentrated in a rotaryevaporator. After distilling off the solvent and the phosphoric acidtriethyl ester, 25 g of a dark oil which consisted mainly of6-(4'-methoxy-phenyl)-4,6-dichloro-3,3-dimethyl-hex-5-enoic acid ethylester and which could be further processed according to process variant1(a) (Example 1) remained.

EXAMPLE 8 (process 7)

7.9 g of 6-(4'-methoxy-phenyl)-6-oxo-4-chloro-3,3-dimethyl-hexanoic acidethyl ester were dissolved in 50 ml of toluene, and 6 g of phosphoruspentachloride were added at room temperature. The mixture wassubsequently stirred at room temperature for 9 hours, poured into 100 mlof ice-water and rendered neutral and the toluene phase was separatedoff. After drying the toluene phase and distilling off the toluene atroom temperature, 68 g of an oil which, according to the NMR spectrum,consisted of 6-(4'-methoxy-phenyl)-4,6,6-trichloro-3,3-dimethyl-hexanoicacid ethyl ester remained. The oil could be reacted further according toprocess variant 1(b).

EXAMPLE 9 (process 8)

26.2 g of 3,3-dimethyl-4-(4'-methoxy-phenacyl)-γ-butyrolactone weredissolved in 500 g of toluene, and 46 g of phosphorus pentachloride wereadded. The mixture was subsequently stirred at room temperature for 18hours and phosphorus oxychloride and toluene were then distilled off atroom temperature in vacuo. 37 g of a brown oil which was identified as6-(4'-methoxy-phenyl)-4,6,6-trichloro-3,3-dimethyl-hexanecarboxylic acidchloride by IR and NMR remained.

EXAMPLE 10 (process 11)

78.6 g of 3,3-dimethyl-4-(4'-methoxy-phenacyl)-γ-butyrolactone weredissolved in 500 ml of ethanol, and dry hydrogen chloride was passed inuntil the temperature had reached 50° C. A slow stream of hydrogenchloride was then passed through the solution at 50° C., initially whilecooling, for 3 hours, and then continued to be passed in until themixture reached room temperature again. Distilling off the ethanol invacuo gave 98 g of6-(4'-methoxy-phenyl)-6-oxo-4-chloro-3,3-dimethyl-hexanoic acid ethylester.

EXAMPLE 11 (process 11)

131 g of 3,3-dimethyl-4-(4'-methoxy-phenacyl)-γ-butyrolactone weredissolved in 215 g of thionyl chloride in a 0.7 liter autoclave with aglass liner. 100 g of ethanol were then pumped in and the mixture waskept at 50° C. for 4 hours. After cooling and letting down, excessthionyl chloride and sulphurous acid ethyl ester were distilled off. Theresidue essentially consisted of6-(4'-methoxy-phenyl)-6-oxo-4-chloro-3,3-dimethyl-hexanoic acid ethylester.

EXAMPLE 12 (process 11)

131 g of 3,3-dimethyl-4-(4'-methoxy-phenacyl)-γ-butryolactone weredissolved in 215 g of thionyl chloride in a 0.7 liter autoclave with aglass liner. 100 g of methanol were then pumped in and the mixture washeated to 50° C. for 4 hours. After working up as in Example 10,6-(4'-methoxy-phenyl)-6-oxo-4-chloro-3,3-dimethyl-hexanoic acid methylester was obtained.

EXAMPLE 13 (process 12)

71 g (0.5 mol) of 3,3-dimethyl-4-pentenoic acid methyl ester wereprepared dropwise to a mixture of 85.5 g (0.5 mol) of p-methoxybenzoylchloride and 130.3 g (0.5 mol) of tin tetrachloride at 20° C., whilecooling with ice. After standing overnight, the reaction mixture hadsolidified. It was taken up in methylene chloride, the methylenechloride mixture was filtered and the filtrate was extracted by shakingwith dilute hydrochloric acid. After drying and stripping off thesolvent in vacuo, a crude product which crystallized completely wasobtained. Recrystallization from ethanol gave3,3-dimethyl-4-(4'-methoxy-phenacyl)-γ-butryolactone of melting point132°-134° C.

EXAMPLE 14 (process 12)

26 g (0.1 mol) of tin tetrachloride were added dropwise to a solution of17.1 g (0.1 mol) of p-methoxybenzoyl chloride and 14.2 g (0.1 mol) of3,3-dimethyl-4-pentenoic acid methyl ester in 100 ml of methylenechloride at 0° and the mixture was then heated under reflux for 8 hours,until the evolution of gas had ended. After working up with dilutehydrochloric acid, 23.9 g (91%) of3,3-dimethyl-4-(4'-methoxyphenacyl)-γ-butyrolactone of melting point132°-134° C. (from ethanol) were obtained.

EXAMPLE 15 (process 14)

17.2 g of 3,3-dimethyl-4-carboxymethyl-γ-butyrolactone were mixed with60 ml of thionyl chloride and the mixture was heated to 80° C. for 1hour. Excess thionyl chloride was then distilled off under normalpressure, the last residues under a waterpump vacuum. The residueconsisted of 3,3-dimethyl-4-chlorocarbonylmethyl-γ-butyrolactone andcould be used directly for process 13. However, it could also be furtherpurified by distillation: boiling point: 130°-140° C./0.3 mbar.

EXAMPLE 16 (process 13)

80 g of aluminum chloride were initially introduced into 300 ml ofmethylene chloride, and 59 g of3,3-dimethyl-4-chlorocarbonylmethyl-γ-butyrolactone dissolved in 150 mlof methylene chloride, were added dropwise at 0°-5° C. 32.4 g ofanisole, dissolved in 50 ml of methylene chloride, were then addeddropwise, likewise at 0°-5° C. The mixture was then allowed to come toroom temperature and was subsequently stirred at room temperature for afurther 7 hours. After pouring the batch into ice-water, the organicphase was separated off and washed until neutral. After drying theorganic phase and distilling off the solvent, crude3,3-dimethyl-4-(4'-methoxy-phenacyl)-γ-butyrolactone, which wasrecrystallized from ethanol, was obtained. Melting point: 132°-134° C.

EXAMPLE 17 ##STR32##

4.4 g (0.02 mol) of 3-phenoxy-4-fluoro-benzyl alcohol and 7.1 g (0.02mol) of2,2-dimethyl-3-(2-chloro-2-(4-methoxy-phenyl)-vinyl)-cyclopropanecarboxylicacid chloride were dissolved in 100 ml of anhydrous toluene, and 2.5 gof pyridine, dissolved in 50 ml of anhydrous toluene, were addeddropwise at 20°-25° C., while stirring. The mixture was then stirred at25°-35° C. for a further 3 hours. The reaction mixture was poured into150 ml of water, to which 10 ml of concentrated hydrochloric acid wereadded, and the organic phase was separated off and washed again with 100ml of water. The toluene phase was then dried over sodium sulphate andthe solvent was distilled under a waterpump vacuum. Last residues ofsolvent were removed by brief incipient distillation at a bathtemperature of 60° C./1 mm Hg. 8.1 g (84.5% of theory) of2,2-dimethyl-3-(2-chloro-2-(4-methoxyphenyl)-vinyl)-cyclopropanecarboxylicacid (4-fluoro-3-phenoxy-benzyl)-ester were obtained.

The following compound was obtained analogously: ##STR33##

The pesticidal activity of the compounds of this invention isillustrated by the following example:

EXAMPLE 18

Phaedon larvae test

Solvent: 3 parts by weight of acetone

Emulsifier: 1 part by weight of alkylaryl polyglycol ether

To produce a suitable preparation of active compound, 1 part by weightof the active compound was mixed with the stated amount of solventcontaining the stated amount of emulsifier and the concentrate wasdiluted with water to the desired concentration.

Cabbage leaves (Brassica oleracea) were treated by being dipped into thepreparation of the active compound and were infested with mustard beetlelarvae (Phaedon cochleariae), as long as the leaves were still wet.

After the specified periods of time, the degree of destruction wasdetermined in %: 100% meant that all of the beetle larvea had beenkilled whereas 0% meant that none of the beetle larvae had been killed.

In this test, for example, the compound of Example 17 showed highactivity.

It will be appreciated that the instant specification and examples areset forth by way of illustration and not limitation, and that variousmodifications and changes may be made without departing from the spiritand scope of the present invention.

We claim:
 1. A compound selected from the group consisting of ##STR34##in which R is C₁₋₄ -alkyl or, ##STR35## R⁴ is hydrogen, cyano orethynyl, R⁵ and R⁶ each independently is hydrogen or fluorine,R¹ isalkoxy or alkylthio, either of which may be optionally substituted byhalogen, R² is hydrogen or alkoxy, or R¹ and R² together are optionallyhalogen-substituted alkylenedioxy, and R³ is hydrogen or chlorine.
 2. Acompound according to claim 1, in which said compound is ##STR36##
 3. Acompound according to claim 1, in which said compound is ##STR37##
 4. Acompound according to claim 1, in which said compound is ##STR38##